This proposal concerns the isolation of adhesion-fimbrial (fim+) genes from Streptococcus sanguis and the expression of these genes in E. coli. The fimbrial proteins produced in E. coli will be tested for their feasibility as a vaccine to block adhesion of S. sanguis and as competitive inhibitors of the adhesion of S. sanguis to saliva-coated hydroxyapatite (an in vitro model system for the tooth surface). Isolation of the genes involves transformation of our fim- S. sanguis mutants with S. sanguis DNA cloned in E. coli. Fimbrial proteins will be detected by immunological methods utilizing our polyspecific and monoclonal antisera for fimbrial antigens. The efficacy of these proteins to block adhesion of S. sanguis to saliva-coated hydroxyapatite will be tested by standard methods. This work may provide a practical solution to reducing the incidence of plaque formation and dental caries. At the very least, genes involved in adherence will be cloned and the foundation for determining the regulation and control of Streptococcal adherence to smooth surfaces will be laid.